US4942490A - Thin layer magnetic read/write head - Google Patents

Thin layer magnetic read/write head Download PDF

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Publication number
US4942490A
US4942490A US07/221,455 US22145588A US4942490A US 4942490 A US4942490 A US 4942490A US 22145588 A US22145588 A US 22145588A US 4942490 A US4942490 A US 4942490A
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US
United States
Prior art keywords
magnetic
substrate
flank
pole
poles
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US07/221,455
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English (en)
Inventor
Jean-Claude Lehureau
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Thales SA
Original Assignee
Thomson CSF SA
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Assigned to THOMSON-CSF reassignment THOMSON-CSF ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: LEHUREAU, JEAN-CLAUDE
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Publication of US4942490A publication Critical patent/US4942490A/en
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Expired - Lifetime legal-status Critical Current

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    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/127—Structure or manufacture of heads, e.g. inductive
    • G11B5/31—Structure or manufacture of heads, e.g. inductive using thin films
    • G11B5/3163—Fabrication methods or processes specially adapted for a particular head structure, e.g. using base layers for electroplating, using functional layers for masking, using energy or particle beams for shaping the structure or modifying the properties of the basic layers
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/127—Structure or manufacture of heads, e.g. inductive
    • G11B5/31—Structure or manufacture of heads, e.g. inductive using thin films
    • G11B5/3109—Details
    • G11B5/3116—Shaping of layers, poles or gaps for improving the form of the electrical signal transduced, e.g. for shielding, contour effect, equalizing, side flux fringing, cross talk reduction between heads or between heads and information tracks
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/127—Structure or manufacture of heads, e.g. inductive
    • G11B5/31—Structure or manufacture of heads, e.g. inductive using thin films
    • G11B5/3176—Structure of heads comprising at least in the transducing gap regions two magnetic thin films disposed respectively at both sides of the gaps
    • G11B5/3179—Structure of heads comprising at least in the transducing gap regions two magnetic thin films disposed respectively at both sides of the gaps the films being mainly disposed in parallel planes
    • G11B5/3183—Structure of heads comprising at least in the transducing gap regions two magnetic thin films disposed respectively at both sides of the gaps the films being mainly disposed in parallel planes intersecting the gap plane, e.g. "horizontal head structure"

Definitions

  • the invention concerns a write/read head in thin layers and a method for manufacturing it which can be applied especially to magnetic heads.
  • the gap of the magnetic head is made by superimposing magnetic layers consituting the first magnetic pole, a non-magnetic layer consituting the gap itself and, finally, another succession of magnetic layers constituting the second pole.
  • the unit is etched so as to define the height of the gap corresponding to the track width. After sawing, this gap is ground so as to adjust the depth of the gap.
  • thin layer heads differ in the nature of the substrates, superstrate and layers used as well as in the mode of manufacturing the coil.
  • the mode of manufacturing the gap is always identical to the one mentioned above.
  • the operation for adjusting the depth of the gap is done individually and is very complex. For, this depth should not exceed about ten microns, otherwise there is the risk of excessively reducing the efficiency of the head.
  • the sawing operation itself gives lack of precision of several tens of microns.
  • the known technology for thin layer magnetic heads thus comes up mainly against the difficulties entailed by a stage for the individual grinding of the heads, which is very costly and has a low success rate.
  • the invention therefore provides for integrating this grinding stage in the operations prior to the sawing of the substrate, thus reducing its cost by a ratio close to the level of integration of the heads on the substrate, which may reach a rate of 1000. Furthermore, according to the invention, the type of head made is more efficient than prior art heads.
  • the invention therefore concerns a magnetic write/read head in thin layers characterized in that it comprises:
  • a first magnetic circuit pole located on this main side and having a first flank forming an angle with the main side;
  • a second magnetic circuit pole located on the main side with a layer of non/magnetic material located between the second pole and the main side, this second pole also having a second flank which is substantially perpendicular to the main side and defines a gap of substantially constant thickness with the first flank.
  • the invention also concerns a method for making a magnetic head in thin layers comprising the following successive steps:
  • FIG. 1 shows a section, in perspective, of an embodiment of a magnetic head in thin layers according to the invention
  • FIG. 2 shows a sectional view of the head of FIG. 1 with the magnetic field induction circuits
  • FIG. 3 shows a first alternative embodiment of a magnetic head according to the invention
  • FIG. 4 shows a second alternative embodiment of a magnetic head according to the invention
  • FIGS. 5 and 6 show an embodiment of a magnetic head according to the invention wherein magnetic field induction coils are deposited on the same side of the substrate as the magnetic poles of the head;
  • FIGS. 7 to 11 show different stages in the accomplishing of the method according to the invention.
  • FIG. 12 shows a method for the collective making of magnetic heads according to the invention.
  • This head has a substrate part or supporting part 1 with a plane side 10.
  • This plane side 10 has a first magnetic head pole 2 which has a flank 20 forming an angle with the plane of the side 10. According to the embodiment shown in FIG. 1, the flank 20 is substantially perpendicular to the plane of the side 10.
  • the side 10 also bears a layer 4 of a non-magnetic material which covers the flank 20 of the first pole 2.
  • the layer 4 has a second pole 3, a flank 30 of which is substantially perpendicular to the plane of the side 10 and parallel to the flank 20.
  • the flanks 20 and 30 define a gap 5 between the poles 2 and 3.
  • the upper sides of the poles 2 and 3 and the non-magnetic layer 4 are at the same level, at least at the location of the gap 5.
  • a magnetic support (not shown) placed before this gap 5 is used to connect the two poles magnetically and close the magnetic circuit of the head.
  • FIG. 2 represents a cross-sectional view of the head of FIG. 1.
  • the supporting part 1 is made of a non-magnetic material such as glass, and its thickness is small so that a magnetic writing or reading field goes through it without excessive loss.
  • Magnetic field induction coils, 7 and 7' are placed on the magnetic circuit near the ends 60 and 61. These coils induce a magnetic field which flows through the poles 2 and 3 in the direction of the arrows 0 in FIG. 2.
  • This fiqure shows that a magnetic support, for example a magnetic tape, which would be placed on the upper surface of the poles 2 and 3, would magnetically couple the two poles above the gap.
  • the head shown in FIG. 23 thus constitutes a write/read magnetic head.
  • the upper side of the head is plane. As shown in FIG. 3, it can also have a curved convex shape.
  • the supporting part 1, especially its side 10, is curved.
  • the poles 2 and 3, and non-magnetic layer 4, are made on this side 10 and therefore have a curved shape. It must be noted that the ends 60 and 61 of the magnetic circuit 6 should be curved to match the shape of the part 1.
  • a head of this type can be used, more especially, in write/read devices using magnetic tapes where the tape can be better placed flat against the head.
  • the curve of the head can be limited to a region surrounding the gap 5.
  • the supporting part 1 is more curved only in a small region and the magnetic circuit be designed so that its ends 60 and 61 are matched to the plane parts of the part 1, thus facilitating the making of the circuit 6.
  • This head comprises a substrate wafer 8 made of a magnetic material unlike in the embodiments described earlier. On this substrate wafer 8, there is placed a part 9, made of a magnetic material, with a curved convex section so that head can be given a bulging shape.
  • a first coil 7 is made on the substrate 8 and the part 9. This coil 7 may have a helical shape, for example, and one part of the coil overlaps the part 9. It is made, for example, by silk-screen process.
  • a first magnetic pole 2 is in contact, through a part 21 with the substrate 8, with the center of the helical coil. Futhermore, through a part 22, it overlaps the coil 7 and the part 9. It has a flank 20 located sudstantially in the middle of the part 9.
  • a layer of non-magnetic material 4 covers the part 9, the substrate 1 and the flank 20 of the pole 2.
  • a second helical coil 7' similar to the first coil 7, lies on the layer of the non-magnetic material 4 with a portion overlapping the part 9.
  • a second magnetic pole 3 is in contact, through a part 31, with the layer 4 at the center of the coil 7'.
  • flanks 20 and 30 thus define the gap of the magnetic head.
  • a layer of a magnetic material is deposited on a side 10 of a substrate 1, and then, in this layer, a magnetic pole 2 is cut out, having at least one flank 20 which is substantially perpendicular to the side 10 of the substrate 1.
  • a layer of a non-magnetic material 4 is deposited.
  • a layer of magnetic material is deposited, and then a magnetic pole 3 is cut out in this layer, with a flank 30 facing the flank 20 of the pole 2.
  • a machining operation is done followed by a grinding operation, the effect of which is to remove the insulant layer located on the magnetic pole 2 and to make the two poles 2 and 3 flush with the two flanks 20 and 30 which define the gap of the magnetic head as shown on FIG. 1.
  • the method of the invention enables the making of several heads, thus described, on one and the same substrate.
  • a fifth step for cutting out the heads thus made collectively.
  • This fiqure shows a set of magnetic heads 2 and 3 lying on a substrate wafer 1.
  • pairs of coils such as 7--7', are made molded in a non-magnetic material. These coils 7--7' are made with the same pitch as the magnetic poles 2-3 so that they can be made put in correspondence with one another.
  • the magnetic circuits 6 are made of a material such as ferrite. These magnetic circuits have pairs of blocks 60, 60' with the same pitch as the magnetic coils so that a pair of blocks can be associated with each pair of coils.
  • the substrate wafer 1, carrying the magnetic poles 2, 3, is then associated, as shown in FIG. 12, with the set of coils and the ferrite magnetic circuits 6 in such a way that, with each pair of poles 2, 3, there is associated a pair of coils 7, 7' and a pair of ferrite blocks 60, 60'.
  • the fifth step mentioned earlier provides for separating each magnetic head individually by cutting out along the dots and dashes shown to the right of FIG. 12.
  • These mesas cover a zone which will include, after manufacturing, the gap 5 of the head.
  • This coil has a central part 21 without any winding, and overlaps a part of the mesa 9.
  • the first step described earlier can thus be used to make a first pole 2, a part 21 of which is at the center of the coil 7 and substantially reaches the middle of the mesa 9.
  • the second step for depositing a layer insulant is accomplished as described above.
  • This coil also has a central part 31 wihtout any winding and overlaps a part of the mesa 9.
  • the third step for making a second magnetic pole 3, as described above, is undertaken.
  • This pole 3 is made in such a way that a part 31 is at the center of the coil 7', and another part 32 covers the coil 7' and faces the first pole 2.
  • the fourth machining and grinding step is then made as described above.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Magnetic Heads (AREA)
  • Magnetic Record Carriers (AREA)
US07/221,455 1986-10-28 1987-10-28 Thin layer magnetic read/write head Expired - Lifetime US4942490A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8614974 1986-10-28
FR8614974A FR2605783B1 (fr) 1986-10-28 1986-10-28 T ete magnetique d'enregistrement/lecture en couches minces et son procede de realisation

Publications (1)

Publication Number Publication Date
US4942490A true US4942490A (en) 1990-07-17

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ID=9340272

Family Applications (1)

Application Number Title Priority Date Filing Date
US07/221,455 Expired - Lifetime US4942490A (en) 1986-10-28 1987-10-28 Thin layer magnetic read/write head

Country Status (7)

Country Link
US (1) US4942490A (fr)
EP (2) EP0270404B1 (fr)
JP (1) JP2935365B2 (fr)
DE (2) DE3752246T2 (fr)
ES (2) ES2127880T3 (fr)
FR (1) FR2605783B1 (fr)
WO (1) WO1988003307A1 (fr)

Cited By (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5189580A (en) * 1989-06-30 1993-02-23 Ampex Corporation Ultra small track width thin film magnetic transducer
US5490028A (en) * 1994-08-26 1996-02-06 Aiwa Research And Development, Inc. Thin film magnetic head including an integral layered shield structure
US5544774A (en) * 1994-08-26 1996-08-13 Aiwa Research And Development, Inc. Method of eliminating pole recession in a thin film magnetic head
US5563754A (en) * 1994-08-26 1996-10-08 Aiwa Research And Development, Inc. Thin film magnetic head including a durable wear layer and gap structure
US5671106A (en) * 1994-11-25 1997-09-23 Thomson-Csf Matrix magnetic recording/reading head
US5673474A (en) * 1994-08-26 1997-10-07 Aiwa Research And Development, Inc. Method of fabricating a thin film magnetic head including layered magnetic side poles
US5745329A (en) * 1995-09-12 1998-04-28 Thomson-Csf Magnetic recording/reading head
US5748417A (en) * 1994-08-26 1998-05-05 Aiwa Research And Development, Inc. Thin film magnetic head including layered magnetic side poles
US5754377A (en) * 1994-08-26 1998-05-19 Aiwa Research And Development, Inc. Thin film magnetic head including an elevated gap structure
US5777824A (en) * 1994-08-26 1998-07-07 Aiwa Research And Development, Inc. Side-disposed thin film magnetic head and method of fabrication thereof
US5801909A (en) * 1994-08-26 1998-09-01 Aiwa Research And Development, Inc. Thin film magnetic head including durable wear layer and non-magnetic gap structures
US5853558A (en) * 1995-02-17 1998-12-29 Aiwa Research And Development Inc. Method of fabricating a thin film conductor coil assembly
US5909346A (en) * 1994-08-26 1999-06-01 Aiwa Research & Development, Inc. Thin magnetic film including multiple geometry gap structures on a common substrate
US5926350A (en) * 1996-03-15 1999-07-20 International Business Machines Corporation Dual gap horizontal thin film inductive head
US5973890A (en) * 1994-07-26 1999-10-26 Thomson-Csf Magnetic head with saturable element between the poles outside of the gap
US6069015A (en) * 1996-05-20 2000-05-30 Aiwa Research And Development, Inc. Method of fabricating thin film magnetic head including durable wear layer and non-magnetic gap structure
US6091581A (en) * 1994-08-26 2000-07-18 Aiwa Co., Ltd. Thin film magnetic head including a separately deposited diamond-like carbon gap structure and magnetic control wells
US6253445B1 (en) 1998-02-24 2001-07-03 Samsung Electronics Co., Ltd. Planar thin film head and method for forming a gap of a planar thin film magnetic head
US6650496B2 (en) 2001-05-15 2003-11-18 Phs Mems Fully integrated matrix magnetic recording head with independent control
US20040027964A1 (en) * 2000-10-17 2004-02-12 Jean-Claude Lehureau Medium for recording optically readable data, method for making same and optical system reproducing said data
US6778669B1 (en) 1998-11-24 2004-08-17 Thomson-Csf Quantum encryption device
US20040246487A1 (en) * 2001-05-15 2004-12-09 Jean-Claude Lehureau Optical fibre gyro
US6958956B1 (en) 1999-08-10 2005-10-25 Thales Magneto-optical reading device for multi-track magnetic tapes
US7130152B1 (en) 1999-04-01 2006-10-31 Storage Technology Corporation High track density magnetic recording head

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4912584A (en) * 1988-03-09 1990-03-27 Digital Equipment Corporation Method for fabricating magnetic recording poles
FR2639137B1 (fr) * 1988-11-15 1990-12-21 Thomson Csf Tete magnetique a entrefer saturable et dispositif matriciel comportant un ensemble de telles tetes
FR2640070A1 (fr) * 1988-12-06 1990-06-08 Thomson Csf Tete magnetique planaire d'enregistrement ´ lecture et procede de realisation
FR2648940B1 (fr) * 1989-06-27 1991-09-06 Thomson Csf Procede de realisation de tete magnetique multipiste et tete magnetique multipiste
FR2649526B1 (fr) * 1989-07-04 1991-09-20 Thomson Csf Procede de fabrication de tetes magnetiques planaires par alveolage d'une plaquette non magnetique, et tetes magnetiques obtenues par un tel procede
FR2652670B1 (fr) * 1989-10-03 1995-06-23 Thomson Csf Tete de lecture magnetooptique a haute resolution.
JP3200060B2 (ja) * 1990-09-12 2001-08-20 ソニー株式会社 薄膜磁気ヘッド
FR2727556B1 (fr) * 1994-11-29 1997-01-03 Thomson Csf Procede de realisation d'une tete magnetique d'enregistrement/lecture et tete d'enregistrement/lecture

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JPS5573913A (en) * 1978-11-30 1980-06-04 Victor Co Of Japan Ltd Magnetic head
JPS57141009A (en) * 1981-02-23 1982-09-01 Hitachi Ltd Thin film magnetic head and its production
JPS5853019A (ja) * 1981-09-25 1983-03-29 Hitachi Ltd 磁気ヘツドの製造方法
US4399479A (en) * 1981-02-04 1983-08-16 Eastman Kodak Company Thin film magnetic head having good low frequency response
JPS60150219A (ja) * 1984-01-18 1985-08-07 Hitachi Ltd 薄膜磁気ヘツドの製造方法
JPS61151818A (ja) * 1984-12-26 1986-07-10 Hitachi Ltd 薄膜磁気ヘツド

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US3478341A (en) * 1966-07-11 1969-11-11 Ncr Co Random access magnetic disc storage device with peripheral bearing means
US3601871A (en) * 1968-09-30 1971-08-31 Texas Instruments Inc Method for fabricating magnetic read-write head array and product
DE2819208C2 (de) * 1978-05-02 1984-10-31 Siemens AG, 1000 Berlin und 8000 München Mehrfach-Dünnschicht-Magnetkopf zur Bandaufzeichnung von Hochfrequenzsignalen
JPS55132519A (en) * 1979-04-03 1980-10-15 Fujitsu Ltd Manufacture for thin film magnetic head
JPS5683823A (en) * 1979-12-11 1981-07-08 Fujitsu Ltd Production for horizontal thin film magnetic head
JPS56145517A (en) * 1980-04-14 1981-11-12 Fujitsu Ltd Thin-film magnetic head
JPS5930227A (ja) * 1982-08-10 1984-02-17 Matsushita Electric Ind Co Ltd 磁気ヘツドの製造方法
JPS60121508A (ja) * 1983-12-05 1985-06-29 Yokogawa Hokushin Electric Corp 磁気ヘッド装置およびその製造方法
JPS60191407A (ja) * 1984-03-12 1985-09-28 Hitachi Ltd 磁気ヘツド
JPS615404A (ja) * 1984-06-18 1986-01-11 Matsushita Electric Ind Co Ltd 垂直磁化型磁気ヘツド
JPS6139206A (ja) * 1984-07-28 1986-02-25 Hitachi Ltd 磁気ヘツド装置
JPS6139914A (ja) * 1984-07-31 1986-02-26 Konishiroku Photo Ind Co Ltd 磁気ヘツド

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5573913A (en) * 1978-11-30 1980-06-04 Victor Co Of Japan Ltd Magnetic head
US4399479A (en) * 1981-02-04 1983-08-16 Eastman Kodak Company Thin film magnetic head having good low frequency response
JPS57141009A (en) * 1981-02-23 1982-09-01 Hitachi Ltd Thin film magnetic head and its production
JPS5853019A (ja) * 1981-09-25 1983-03-29 Hitachi Ltd 磁気ヘツドの製造方法
JPS60150219A (ja) * 1984-01-18 1985-08-07 Hitachi Ltd 薄膜磁気ヘツドの製造方法
JPS61151818A (ja) * 1984-12-26 1986-07-10 Hitachi Ltd 薄膜磁気ヘツド

Cited By (27)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5189580A (en) * 1989-06-30 1993-02-23 Ampex Corporation Ultra small track width thin film magnetic transducer
US5973890A (en) * 1994-07-26 1999-10-26 Thomson-Csf Magnetic head with saturable element between the poles outside of the gap
US6091581A (en) * 1994-08-26 2000-07-18 Aiwa Co., Ltd. Thin film magnetic head including a separately deposited diamond-like carbon gap structure and magnetic control wells
US5737825A (en) * 1994-08-26 1998-04-14 Aiwa Research & Development, Inc. Method of making thin film magnetic head including a durable wear layer and gap structure
US5490028A (en) * 1994-08-26 1996-02-06 Aiwa Research And Development, Inc. Thin film magnetic head including an integral layered shield structure
US5673474A (en) * 1994-08-26 1997-10-07 Aiwa Research And Development, Inc. Method of fabricating a thin film magnetic head including layered magnetic side poles
US5950301A (en) * 1994-08-26 1999-09-14 Aiwa Research And Development, Inc. Method for fabricating thin flim magnetic head including an elevated gap structure
US5754377A (en) * 1994-08-26 1998-05-19 Aiwa Research And Development, Inc. Thin film magnetic head including an elevated gap structure
US5748417A (en) * 1994-08-26 1998-05-05 Aiwa Research And Development, Inc. Thin film magnetic head including layered magnetic side poles
US5544774A (en) * 1994-08-26 1996-08-13 Aiwa Research And Development, Inc. Method of eliminating pole recession in a thin film magnetic head
US5777824A (en) * 1994-08-26 1998-07-07 Aiwa Research And Development, Inc. Side-disposed thin film magnetic head and method of fabrication thereof
US5801909A (en) * 1994-08-26 1998-09-01 Aiwa Research And Development, Inc. Thin film magnetic head including durable wear layer and non-magnetic gap structures
US5563754A (en) * 1994-08-26 1996-10-08 Aiwa Research And Development, Inc. Thin film magnetic head including a durable wear layer and gap structure
US5909346A (en) * 1994-08-26 1999-06-01 Aiwa Research & Development, Inc. Thin magnetic film including multiple geometry gap structures on a common substrate
US5671106A (en) * 1994-11-25 1997-09-23 Thomson-Csf Matrix magnetic recording/reading head
US5853558A (en) * 1995-02-17 1998-12-29 Aiwa Research And Development Inc. Method of fabricating a thin film conductor coil assembly
US5745329A (en) * 1995-09-12 1998-04-28 Thomson-Csf Magnetic recording/reading head
US5926350A (en) * 1996-03-15 1999-07-20 International Business Machines Corporation Dual gap horizontal thin film inductive head
US6069015A (en) * 1996-05-20 2000-05-30 Aiwa Research And Development, Inc. Method of fabricating thin film magnetic head including durable wear layer and non-magnetic gap structure
US6253445B1 (en) 1998-02-24 2001-07-03 Samsung Electronics Co., Ltd. Planar thin film head and method for forming a gap of a planar thin film magnetic head
US6778669B1 (en) 1998-11-24 2004-08-17 Thomson-Csf Quantum encryption device
US7130152B1 (en) 1999-04-01 2006-10-31 Storage Technology Corporation High track density magnetic recording head
US6958956B1 (en) 1999-08-10 2005-10-25 Thales Magneto-optical reading device for multi-track magnetic tapes
US20040027964A1 (en) * 2000-10-17 2004-02-12 Jean-Claude Lehureau Medium for recording optically readable data, method for making same and optical system reproducing said data
US7149173B2 (en) 2000-10-17 2006-12-12 Thales Medium for recording optically readable data, method for making same and optical system reproducing said data
US6650496B2 (en) 2001-05-15 2003-11-18 Phs Mems Fully integrated matrix magnetic recording head with independent control
US20040246487A1 (en) * 2001-05-15 2004-12-09 Jean-Claude Lehureau Optical fibre gyro

Also Published As

Publication number Publication date
JPH01501105A (ja) 1989-04-13
DE3750607T2 (de) 1995-01-19
ES2060605T3 (es) 1994-12-01
EP0618568A3 (fr) 1995-05-10
WO1988003307A1 (fr) 1988-05-05
EP0618568A2 (fr) 1994-10-05
JP2935365B2 (ja) 1999-08-16
EP0270404B1 (fr) 1994-09-28
DE3752246T2 (de) 1999-06-17
DE3750607D1 (de) 1994-11-03
FR2605783B1 (fr) 1992-05-15
FR2605783A1 (fr) 1988-04-29
ES2127880T3 (es) 1999-05-01
EP0270404A1 (fr) 1988-06-08
DE3752246D1 (de) 1999-02-04
EP0618568B1 (fr) 1998-12-23

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